It takes about 140 ms for a signal to go around the world once by means of
the ionosphere. I have experienced this several times while DXing; the best
was when I could transmit into a 2 element quad while receiving on a small
Sterba curtain.  This was in Cedar Rapids, at my K0DDA station, in December,
1970.  Sometimes, when conditions are right, using high antennas, the
round-the-world echo can be heard a second or third time also.  Full-breakin
CW or a second receiver is good for this if you are going to hear your own
station doing this.  Often, but not always, this echo occurs along the grey
line, and at times when the band is barely open because you are very close
to the MUF for the direction you are aiming.

At the same Cedar Rapids location, sometime in 1973 or 1974, while working
in a traffic net on 80 CW, I experienced an echo with a somewhat longer
delay.  It can usually only be heard by people within a few miles of the
transmitting station. Solar activity has to be pretty low, so that the
signal, even on 80 meters, can escape into space and return.  This
phenomenon has occured to many people on CW and SSB at unpredictable times,
was writtten up in QST and other publications several times. I thinkthat the
time delay for this echo is about 350 ms, which would be long enough for you
to hear a word when the VOX releases.  The explanation for this type of
long-delayed echo, which was written up in QST in about 1987/88, and makes a
lot of sense to me, is that the signal is going into space,following a line
of the earth's magnetic field.  The signal travels thousands of miles into
space, follows the curved line down to earth at a particular spot in the
Southern Hemisphere, where it is reflected from the ground or the top of the
ionosphere there and returns to your QTH and vicinity.  A somewhat similar
phenomenon causes "whistlers", very-low-frequency sounds when a lightning
stroke's static crash returns to the source spread out in time, with the
higher frequency components of the crash arriving before the lower
frequencies do.

As for delays longer than these, some kind of recording/retransmitting
mechanism has to be involved, and I just am very sketpical.

73 -- Lloyd, W3IUU
----- Original Message ----- 
From: "Butch Bussen" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, March 08, 2007 9:41 AM
Subject: Re: question about a radio phenomenome?


> I think it is called l d e or long delayed echo.
>
> I actually experienced one of these one night on 80 meters talking to some
> friends in Nebraska.  We had a delay of about a second.  You could let up
> on the mike and hear your last word or so.  Two or three of us experienced
> it, although to the other person the signal sounded fine.  Now, one second
> isn't much, but consider how far that signal had to travel, bouncing
> around the atmosphere or whatever.  Quite a bit for 186,000 miles
> 73s
> Butch Bussen
> wa0vjr


Lloyd Rasmussen, Kensington, Maryland
Home:  http://lras.home.sprynet.com
Work:  http://www.loc.gov/nls
 
> -----Original Message-----
> From: For blind ham radio operators [mailto:[log in to unmask]]
> On Behalf Of Butch Bussen
> Sent: Thursday, March 08, 2007 12:41 PM
> To: [log in to unmask]
> Subject: Re: question about a radio phenomenome?
> 
> I think it is called l d e or long delayed echo.
> 
> I actually experienced one of these one night on 80 meters talking to some
> friends in Nebraska.  We had a delay of about a second.  You could let up
> on the mike and hear your last word or so.  Two or three of us experienced
> it, although to the other person the signal sounded fine.  Now, one second
> isn't much, but consider how far that signal had to travel, bouncing
> around the atmosphere or whatever.  Quite a bit for 186,000 miles
> 73s
> Butch Bussen
> wa0vjr